Crimped piston/membrane accumulator

Abstract

An accumulator for a fluid system includes a canister and an end cap at one or both ends of the canister. The end cap has a cylindrical peripheral surface, with a groove or channel having gradually rounded or curved sidewalls, formed circumferentially around the cap, and spaced from the axial ends of the cap. An annular, radially-outward projecting flange is provided at the axially outer end of the cap, and serves as a locating feature for the cap when it is inserted into the canister. A forming tool such as a crimping machine is used to mechanically deform the canister into the groove. The rounded shape of the groove creates a permanent, fluid-tight attachment with the canister. The accumulator can include either a piston or bladder.

What is claimed is:  
     
       1. An accumulator including an elongated cylindrical canister and a piston located within the canister and slideable axially within the canister to divide the canister into separate chambers, the piston having a cylindrical peripheral surface, and sealing means disposed between the peripheral surface of the cylinder and the canister for providing a fluid-tight seal between the chambers; an end cap enclosing an end of the canister, the end cap having an outer cylindrical surface closely received in the canister, with an annular groove formed in the outer surface of the end cap at a location spaced from the axial ends of the end cap, the groove including a flat bottom and at least one sidewall with a rounded portion, the side wall interconnecting the flat bottom with the outer cylindrical surface of the end cap, the canister being mechanically formed into the groove to fix the end cap in a permanent and fluid tight manner to the canister. 
     
     
       2. The accumulator as in  claim 1 , wherein the at least one rounded sidewall is rounded from the flat bottom to the outer cylindrical surface of the end cap. 
     
     
       3. The accumulator as in  claim 1 , wherein the canister is formed into direct contact with the end cap groove. 
     
     
       4. An accumulator including an elongated cylindrical canister and a piston located within the canister and slideable axially within the canister to divide the canister into separate chambers, the piston having a cylindrical peripheral surface, and sealing means disposed between the peripheral surface of the cylinder and the canister for providing a fluid-tight seal between the chambers; an end cap enclosing an end of the canister, the end cap having an outer cylindrical surface closely received in the canister, with an annular groove formed in the outer surface of the end cap at a location spaced from the axial ends of the end cap, the end cap including an annular, radially outward projecting flange at an outer axial end of the end cap, the flange engaging an end of the canister and locating the end cap with respect to the canister when the end cap is inserted into the canister, the canister being mechanically formed into the groove to fix the end cap in a permanent and fluid tight manner to the canister. 
     
     
       5. The accumulator as in  claim 1 , wherein the end cap includes an annular seal groove on an inner axial end of the end cap, and a resilient annular seal located in the seal groove, the seal exposed to pressure within the canister and providing a fluid-tight seal with the canister. 
     
     
       6. An accumulator including an elongated cylindrical canister, an elastic bladder located within the canister and dividing the canister into separate chambers, and sealing means disposed between an open end of the bladder and the canister for providing a fluid-tight seal between the chambers, and end cap enclosing an end of the canister, the end cap having an outer cylindrical surface closely received in the canister, with an annular groove formed in the outer surface of the end cap at a location spaced from the axial ends of the end cap, the groove including a flat bottom and at least one sidewall with a rounded portion, the side wall interconnecting the flat bottom with the outer cylindrical surface of the end cap, the canister being mechanically formed into the groove to fix the end cap in a permanent and fluid tight manner to the canister. 
     
     
       7. The accumulator as in  claim 6 , wherein the at least one rounded sidewall is rounded from the flat bottom to the outer cylindrical surface of the end cap. 
     
     
       8. The accumulator as in  claim 6 , wherein the canister is formed into direct contact with the end cap groove. 
     
     
       9. An accumulator including an elongated cylindrical canister, an elastic bladder located within the canister and and dividing the canister into separate chambers, and sealing means disposed between an open end of the bladder and the canister for providing a fluid-tight seal between the chambers; an end cap enclosing an end of the canister, the end cap having an outer cylindrical surface closely received in the canister, with an annular groove formed in the outer surface of the end cap at a location spaced from the axial ends of the end cap, the end cap including an annular, radially outward projecting flange at an outer axial end of the end cap, the flange engaging an end of the canister and locating the end cap with respect to the canister when the end cap is inserted into the canister, the canister being mechanically formed into the groove to fix the end cap in a permanent and fluid tight manner to the canister. 
     
     
       10. The accumulator as in  claim 6 , wherein the end cap includes an annular seal groove on an inner axial end of the end cap, and a resilient annular seal located in the seal groove, the seal exposed to pressure within the canister and providing a fluid-tight seal with the canister. 
     
     
       11. An accumulator for a fluid system, comprising: 
       an elongated cylindrical canister;  
       responsive means located within the canister to absorb under pressure excess fluid capacity in the fluid system, said responsive means dividing the canister into a pair of chambers;  
       sealing means between the responsive means and the canister for providing a fluid-tight seal between the chambers; and  
       an end cap enclosing an end of the canister, the end cap having an outer cylindrical surface closely received in the canister, with an annular groove formed in the outer surface of the end cap at a location spaced from the axial ends of the end cap, the groove including a flat bottom and at least one sidewall with a rounded portion, the side wall interconnecting the flat bottom with the outer cylindrical surface of the end cap, the canister being mechanically formed into the groove to fix the end cap in a permanent and fluid tight manner to the canister.  
     
     
       12. The accumulator as in  claim 11 , wherein the at least one rounded sidewall is rounded from the flat bottom to the outer cylindrical surface of the end cap. 
     
     
       13. The accumulator as in  claim 11 , wherein the canister is formed into direct contact with the end cap groove. 
     
     
       14. An accumulator including an elongated cylindrical canister, a responsive means located within the canister to absorb under pressure excess fluid capacity in the fluid system, said responsive means dividing the canister into a pair of chambers; and sealing means disposed between the responsive means and the canister for providing a fluid-tight seal between the chambers; an end cap enclosing an end of the canister, the end cap having an outer cylindrical surface closely received in the canister, with an annular groove formed in the outer surface of the end cap at a location spaced from the axial ends of the end cap, the end cap including an annular, radially outward projecting flange at an outer axial end of the end cap, the flange engaging an end of the canister and locating the end cap with respect to the canister when the end cap is inserted into the canister, the canister being mechanically formed into the groove to fix the end cap in a permanent and fluid tight manner to the canister. 
     
     
       15. The accumulator as in  claim 11 , wherein the end cap includes an annular seal groove on an inner axial end of the end cap, and a resilient annular seal located in the seal groove, the seal exposed to pressure within the canister and providing a fluid-tight seal with the canister. 
     
     
       16. A method for assembling an accumulator, comprising: 
       providing an elongated cylindrical canister;  
       locating responsive means within the canister to absorb under pressure excess fluid capacity in the fluid system, said responsive means dividing the canister into a pair of chambers and having sealing means between the responsive means and the canister for providing a fluid-tight seal between the chambers;  
       inserting an end cap into an end of the canister to enclose the end of the canister, the end cap having an outer cylindrical surface closely received in the canister, and an annular groove formed in the outer surface of the end cap at a location spaced from the axial ends of the end cap, and an annular, radially projecting flange at an outer axial end of the end cap, wherein the flange contacts the end of the canister to locate the end cap with respect to the canister; and  
       mechanically forming the canister into the groove to fix the end cap in a permanent and fluid tight manner to the canister.  
     
     
       17. The method as in  claim 16 , wherein the canister is crimped into the groove. 
     
     
       18. The method as in  claim 16 , wherein the canister is formed into direct contact with the end cap groove. 
     
     
       19. The accumulator as in  claim 1 , wherein the mechanical formation of the canister occurs at a location spaced from the end of the canister. 
     
     
       20. The accumulator as in  claim 6 , wherein the mechanical formation of the canister occurs at a location spaced from the end of the canister. 
     
     
       21. The accumulator as in  claim 11 , wherein the mechanical formation of the canister occurs at a location spaced from the end of the canister. 
     
     
       22. The method as in  claim 16 , wherein said mechanically forming step occurs at a location spaced from the end of the canister.